Electric-arc welding.



A. SMITH.

ELECTRIC ARC WELDING.

APPLICATKON FILED AUG. 11. 1914.

Patented Mar. 25, 1919.

5 SHEETS-SHEET 1.

gm-auxin:

A. SMITH,

ELECTRIC ARC WELDING.

APPLICATION FILED AUG. I7. I914.

1,298,590. Patented Mar. 25, 1919.

5 SHEETSSHEET 2.

A. SMITH.

ELECTRIC ARC WELDING.

APPLICATION FILED AUG. 11. I914.

5 SHEETSSHEET 3.

Patented Mar. 25,1919

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A. SMITH.

ELECTRIC ARC WELDING.

APPLICATION FILED AUG. 11, m4.

5 SHEETS-SHEET 4- Patented Mar. 25, 1919.

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ELECTRIC ARC WELDING.

APPLICATION FILED jxuzs= 11. I9l4.

Patented Mar.

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UNITED STA'W a2}.

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ntnomc m WELDING.

.sists in a method of welding wherein the weld is produced by a seriesof steps automatically controlled, the edges of the metal to'be un tedbeing first brought to a welding temperature, then flushed with'moltenmetal and maintained in proper condition to remove the slag and form ahomogeneous weld with the impurities .upon the outside, and finallycuttin ofi the superfluous metal containing said impurities, and leavinga smooth unbroken surface.

Another feature consists in the provision of an automatically controlledmolten metal supply which is regulated in accordance with-the particularconditions demanded by the area ofthe welded surfaces, the rate oftravel of the pipe or other article, the amperage of the currentemployed to effect the. weld, etc. My' invention also contemplates awelding torch or tool from which the are is sprung, which shall benon-consuming, with provision for the circulation of a cooling medium tomaintain the torch below the oxidizing temperature.

The electric weldin of joints as now practised, is mainly e ected by theresistance method in which one terminal. of an electrical circuit isconnected to the work while the other terminal conducts the cur-- rentto the joint which is heated to welding temperature by the resistance ofthe joint, the parts being then united under pressure. This method isessentially carried out at a low voltage (frequently as low as twovolts)- and a very large amperage. This method is not adapted to thecontinuous welding of joints in long pipe lengths having thick wallsrufiliring too long a time to properly heat 1:

Specification of Letters Patent.

I known.

e metal to the fusion i 25;;i i9.f Application 1914. serialhasmav.

point and being wasteful the of energy.

More recently the electric arc has beenem-ISE i plo ed in efiectingcertain kinds of welding,;=-

suc as the well known Bernardos 'systemf i in which the joint or cavity"betweenthe welded while the operator, with a carbon md attached thenegative ir touches the P to be heated and then withdraw strength toestablish the arc, and move -th it a short distance according to thecurrent carbon slowly over the surfaceso as not to,

efiect an extreme local heating until the whole desired fusing heat.

In another process of autogenous weldin by the electric are, known asthe Slaviano process, one terminal is attached to the ob ject to bewelded and the other terminal connected to a holder containin rod of thesame metal that is to part is brought to the proper welded a metal andthe operator, after first making con tact with this metal rod electrode,withdraws it a short distance to establish an arc.

The rod is consumed, the molten metal be-',

ing transferredto the joint, and the opera-Y tor manipulating the holderover the joint until the weld is completed. This process is evidentlyslower than the Bernados rocess, but is more reliable and less liab e toform hard brittle welds, but requires greater skill in maintaining thecorrect arc, as the welding rod has a tendency to stick if in too closecontact while if the rod is too far away the arc ceases.

The use of the electric arcin repairing cracked or broken parts and forfilli cavities in defective castings is now wel The metal parts to beunited are heated by an are from a carbon or graphite.

ais

electrode, usually manipulated by onehand. of the operator,-whilewiththe other hand he brings a metal filler rod into proximity to the are sothat it is fixed and carried 12H.

thereby into welding union with the-part8 of the joint. I Inall priormethods of arc welding, in

so far as I am aware the .degree of su atta ned depends very largelyupon the known as the welding state of iron or skill'of the operator andconsequentl the results are not uniform. The con ition steel is onewhich exists only within a very limited range of temperature. Thepartsto be united are heated within the critical range of temperature,in which the molecules approach, though never arriving at liquidity, andwhich condition is favorable to the interpenetration of the moleculesand consequent weld-union of the surfaces. When additional metal isadded or filled 111, as 1n the processes above descnbed, 1t 1s necessarythat the adjacent edges of the joint to be weld-united should be broughtto the'welding temperature by the heat of the arc in order to edect aproper union and yet not become overheated or burnt, and in this liesthe great difficulty in the manually controlled arc Welding; Y

'VVhen the electrode from which the arc proceeds is of carbon, the weldbecomes un duly hard and brittle because of the additional carboncontent absorbed from the carbon dioxid of the consumed electrode. Theheat of the are is also too intense from a carbon electrode whichincreases the liability to oxidize or burn the metal adjacent the weld.

My invention overcomes the several diflieulties involved in electricwelding by the processes referred to above, by providing a non-consumingmetal electrode which is maintained below an oxidizing temperature. Theedges of the metal adjacent the weld may therefore be brought to theproper welding temperature and in exactly the proper state to combinewith the particles of molten filling metal proceeding in a. fine streamof minute fused globules from the arc of the separate metal electrode,which is being melted and deposited on the work. By maintaining an areseparate from the arc of the welding or consuming metal electrode, I canregulate the current flowing therethrough in proportion to theconditions of the work, while a heating are from the non-consumingelectrode can be regulated to bring the sides of the joint to be weldedto the exact critical welding state of fusion and this condition resultsin a homogeneous weld.

For the purpose ofmore fully disclosing my'invention I shall refer inthe further description to the accompanying drawings, in which-Figure 1is a perspective view of a welding apparatus embodying my invention anddisclosing the several steps which constitute my improved method of arcwelding; Fig. 2 is aside elevation of a similar apparatus, showing alsoa shaping bell in connection with the stand of rolls; Figs. 3 and 4 arevertical sections on the lines 3-3 and 4-4, respectively of Fig. 2;Figs. 5, 6 and 7 are cross sectional views on the lines 5-5, 6-6,

action of this are, the

and 7- 7 of Fig. 2; Fig. 8 is a side elevation, partly in section,showing. another form of my process of welding in which I dispense withthe consuming metal filling electrode and unite the arc-fused edges ofthe joint by compression in passing through the rolls, and then out 01fthe extruded metal which contains the slag; Figs. 9, 10 and 11 arevertical sections on the lines 9-9, 1010, and 1111, respectively of Fig.8; Figs. 12 and 13, are side elevation and top plan views respectivelyofone form of apparatus for controlling the metal filling electrode,with means for automatically feeding the metal rod; Fig. 14 is a sideelevation of mechanism for controlling the are and oscillating the torchwhen it is desired to move the are from side to side across the weld;Fig. 15 is a side elevation, partly in section, of one form of mywater-cooled welding torch for manual use; Fig. 16 is a longitudinalfragmentary section of another form of my portable water-cooled torch;Fig. 17, is a side elevation of my automatically controlled arc-weldingtorch; Fig. 18, is a detail view of a portion of thesame, partly insection, showing the manner of connecting the water-cooling pipes; Fig.19 is a top plan view of the torch shown in Fig. 17 Fig.20 is a sideelevation and Fig. 21, a section on the line 21-21 of Fig. 20, showing amodified form of my torch; Fig. 22 is a side elevation of another formof my automatically controlled water-cooled torch, having a rotary tool,and Fig. 23, is

.an enlarged sectional view of the rotary tool shown in Fig. 22.

I have illustrated in Fig. 1, the general arrangement of apparatusemployed in carrying out my method of arc-welding, as applied to thewelding of joints in the manufacture of welded pipe. Inasmuch as theweld-union is homogeneous, the finished pipe ispractically seamless. Ihave found it advisable to preheat the pipe to about a red heat as thisnot only conserves the energy of the electric are but lessens theliability to internal strains upon cooling by making the gradationsof'heat more uniform. After leaving the preheating furnace l the pipe 2,which is connected to one termi- "nal of the electric circuit is fedunder the electric are 3 springing from the fluidcooled metal torch 3,which heats the edges of the seam or joint to the point of fusion orwelding temperature. In order to produce a successful weld it isabsolutely essential that the entire area of the surfaces to be weldedshould be in a state of fusion.

In this condition, the pipe passes under the are 4 issuing from themetal filling electrode 4", which is carried by the, welding tool 4, therod electrode being automatically fed from the reel 6. Under the minutefused globules of metal are deposited upon the opposite sides and thebottom of the joint until the gap, is completely filled and preferablywith an added amount of metal projecting above the joint. By reason ofthe fused condition of the sides of the joint there will be aninterpenetration of the molecules of the filling metal and the moleculesof the pipe edges, thereby effecting a complete homogeneous weld-unionof the metal of the joint. The metal is maintained in a state of fusionas it passes under the influence of the are 7 issuing from thefluid-cooled. electrode 7. This has the effect of causing the slag withthe impurities to appear in j the surface layer which is removed as thepipe passes under the cutting too1 9, adjusta-bly held in the carrier12. The finished pipe is accurately traced or stralghtened as it passesthrough the rolls 14 in the stand 15. In operating upon pipes of largediameters, an inner mandrel is employed in the manner indicated in Fig.8.

The manner of fluid-cooling the welding torch is shown in Figs. 15 and16, in connection with a portable or hand torch. The head piece 18,having the hollow electrode 3, removably secured thereto, is providedwith channels permitting a constant circulation of the cooling fluidpassing inwardly through the pipe 20 and returning through the pipe 22,each of which is provided with a suitable valve 24. The electric circuitterminal 26, is connected to the pipes 20 and 22, which carry aninsulated hand grip 27.

In Fig. 16, I have shown the cooling pipes, 20 and 22 one within theother. The entire torch may be incased in an insulating protectivecovering as indicated at 29. his protective covering serves not only toinsulate the torch from any object with which it may come in contact,but serves also to protect the metal Walls of the torch from the heatradiated from the metal parts under the are which are at a weldingtemperature.

The insulating sheath thus prevents the propagation of heat from theexterior 'to the interior of the torch and hence conserves the heatdissipating action of the. water flowingthrough the channelsof thetorch.

In'Figs. 1'7, 18 and 19, I have illustrated the form of automaticallycontrolled torch indicated at 3 and 7 in Fig. 1. The cooling pipes 20and 22 which convey the water to the torch head 18, are secured to thepivot block 30 of a lever 30, the block having trunnions pivoted at 32,in the yoke arms 34 of thebase or standard 35. The connection of thefluid-cooling pipes may be made, as indicated, through channels in thepivot block with the supply and outlet pipes 20 and 22.

The end of the lever 30 carries a pivoted core 38, which is in operativerelation with the solenoid coil 39, preferably connected in circuit withthe torch 3. In operation the torch head 18, normally. overbalances .thecore 38, coming into contact with the pipe 2, and thereby establishingthe circuit through the torch and the solenoid coil. The core isimmediately drawn down into the coil, lifting the end of the torch 3from the pipe and thereb establishing an arc, and this is maintained ythe continued pull of the solenoid. In case of any interruption to thecurrent, the arc is interrupted, deenergizing the solenoid andpermitting the torch to drop back into contact with the pipe. Upon therestablishment of the current, the arc will again be automaticallystarted in the manner described. Adjustable 'limit stops 40, 40 may beprovided.

As it is desirable to oscillate the torch 7 so that the arc 7 will shiftfrom one side to the other across the joint to distribute the heat 'overthe weld, I have shown in Figs. 1 and 14, the base 35, adapted toslide/between guideways 42, on the foundation plate 43. The base may beoscillated by means of an electric motor 45, and connecting link 46, or

in any other suitable manner.

The current amperage flowing through the are 4 which springs from thefusible metal electrode 4", and projects a stream of minute fusedglobules of metal into the joint, 'may be regulated to suit theconditions required by the work. The regulation of this current isindependent of the current supplying the heating arc 3. It is desirablethat the supply of fused globules of molten metal is suing from themetal electrode 4 (Figs. 1, 1 2 and 13), should be proportioned to thearea of the joint and to the speed with which the pipe 2, is fed throughthe apparatus and I therefore provide mechanism for automaticallyfeeding the met-a1 rod 4 through the torch 4. As one means ofaccomplishing this purpose. I have shown the rod 4 passing betweenfeed-rollers 48, operatively connected with the motor 50, through gears52, 54 and a speed changing clutch; the latter comprising a frictionroller 56, on the motor shaft which may be shifted laterally to engageeither disk 57 or 57 for reversing the. direction of rotation and movedlongitudinally on the motor shaft to engage the clutch disks atdifferent radial distances to vary the speed. These changes in theclutch mechanism are effected through the lever 58 and controlling rod59. g

In Figs. 2 to 7 inclusive, I have shown an arrangement for carrying outmy method of arc welding in a manner similar to that illustrated in Fig.1, so that the method of operation will be understood without furtherdetailed explanation. A shaping bell roll is carried in bearing blocks67, which may be adjusted vertically to accommodate pipes of varyingdiameters.

In Figs. 8 to 11 inclusive, I have shown a modification of my method ofarc welding in which I dispense with the metal filling electrode and mayalso dispense with the preheating furnace. The pipe 2 is fed over a roll70, and beneath a pair of non-consuming fluid-cooled torches 3, 3,located upon opposite sides of the joint so that the arcs may bring themetal adjacent the joint nearly to the welding temperature. Immediatelyafter passing from the preheating arcs of the torches 3, 3', the pipepasses under the torch 3", so that its arc will raise the entire surfacearea of the joint to the point of fusion. While in this state, the pipeis drawn over the mandrel 72 on the end of the rod 7 3, and compressedbetween the rolls 14: which completely weld the fused sides of the jointand extrude a portion of the metal, together with any slag andimpurities into a fin or protuberance 7 5 which is cut off by the tool 76.

Instead of the fixed electrode attached to the stationary head 18, it issometimes desirable to employ a rotary electrode 80, such as I haveillustrated in Figs. 22 and 23,

- which may be constantly rotated by gearing 81, driven by a motor 82.The casing of the electrode may be connected to fluid inlet and outletpipes-and have an interior diaphragm 84, to cause a complete circulationof the cooling fluid therethrough. The are springs jects.

from the intermediate peripheral rib 80 and is caused to constantlytravel around the perimeter by the rotation.

My fluid cooled torch may be advantageously employed where the arc isused to cut away metal parts. In Figs. 20 and 21, I have shown a form oftorch which is made by doubling a tube 85, of elliptical section uponitself, thereby forming a very narrow tool which can enter contractedspaces or cut narrow groove-s or channels in metal ob- Such an implementis exceedingly useful in cutting away unnecessary parts, such as therisers from steel castings.

While water-cooled electrodes have been used in resistance welding wherethe tool is in contact with the work and the heat is generated by theresistance offered by the joint to the passage of the current; and alsoas electrodes in certain types of electric furnaces, I am the first todevise amethod of arc welding wherein the joint to be welded is heatedby an arc issuing from a fluidcooled electrode and this results in abetter control of the heat, which is less intense than from a carbonelectrode and the electrode is non-consuming, being maintained by thecooling-fluid below the oxidizing temperature.

My method of welding by means of an arc springing from an electrodewhich is maintained in non-consuming condition, not only maintains theintegrity of the electrode but also maintains the integrity or purity ofthe metal of the joints, since the arc does not carry any foreignsubstances over into the 'oint. J The method of arc welding is also newwith my invention wherein the surfaces of the joint are first heated toawelding or nearly welding temperature by a suitable torch, followed bya metal bearing arc issuing from a metal rod which deposits a stream offused metal globules upon the preheated surfaces and simultaneouslysubjects said joint surfaces to the fusing heat of the arc, therebyforming a homogeneous weld.

I have described in detail the particular apparatus illustrated in theaccompanying drawings for the purpose of disclosing my method of weldingand apparatus therefor, but I am aware that many and varied changes maybe made therein within the scope of my claims and without departing fromthe spirit of my invention.

I claim:

1. The method of welding metal joints which comprises heating the metalupon opposite sides of the joint to a welding temperature by an electricarc, and maintaining the integrity of the metal of the joint and of theelectrode from whichthe arc springs by subjecting the latter to theaction of a fluid cooling medium.

2. The method of forming welded metal joints which comprises locallyheating the metal upon opposite sides of the joint to a weldingtemperature, causing an interpenetration of the fused molecules of themetal of the'joint under the action of an electric arc, maintaining theintegrity of the metal of the joint and of the electrode from which thearc springs by subjecting the latter to the action of a fluid coolingmedium, and removing the surface layer of the joint containing the slagand impurities.

3. The method of welding metal joints which comprises heating thearticle containing the joint to be welded to substantially a red heat,heating the metal parts to be welded approximately to the point offusion in an electric arc, maintainingthe integrity of the metal of thejoint and of the electrode from which the arc springs by subjecting thelatter to the action of the fluid cooling medium, and subjecting saidheated joint portions to the action of an arc carryglobules of the samemetal as the trode from which the arc springs by subjecting the latterto the action of the fluid cooling medium, subjecting said heated jointportions to the action of an are carrying fused globules of the samemetal as the joint, and exposing the resultant weld to the action of anare from a non-consuming electrode.

5. The method of electric welding which comprises establishing an arebetween the parts to be Welded and a non-consuming electrode, andheating said parts to approximately the point of fusion, andestablishing an are between said heated parts and an electrode ofsubstantially the same metal as said parts, thereby welding the fusedmetal issuing from the electrode to said parts.

6. The method of electric welding which comprises establishing an arcbetween the parts to be welded and a metal electrode and heating saidparts to approximately the point of fusion, maintaining the integrity ofthe metal of the joint and of the electrode from which the are springsby subjecting the latter to the action of a fluid cooling medium,establishing an arc between said heated parts and an electrode of,substantially the same metal as said parts,

' thereby welding the fused metal dropping from the electrode to saidparts, and subjecting the resulting welded parts to the action of an arcissuing from a non-consuming electrode to thereby cause the slag andimpurities to gather in the surface layer.

7. The method of welding, which comprises heating the metal parts to bewelded qto the point of fusion under the action of 1: an electric arc,and maintaining the Integ- 60. the parts to a rolling operation.

ty of said metal parts and of the electrode atter to the action of afluid cooling medium.

' 8. The method of welding joints between metal parts, which comprisessubjecting the arts to be welded first to the action of an *arc' issuingfrom a non-consuming electrode maintained in allnement with the oint,and

then to the action of an arc issuing from a non-consuming electrodeoscillating across the path of the joint.

9. The method of welding joints between metal parts, which comprisessubjecting the parts to be welded first to the action of an arc issuingfrom a non-consuming electrode maintained in alinement with the joint,and then to the action of an arc issuing from a non-consuming electrodeoscillating across the path of the joint, and then subjecting 10.Apparatus for welding, comprising a non-consuming fluid-cooled metalelectrode, a fusible metal electrode adapted to supply I fused metal tothejoint, and means for supplying metal to replenish said electrode asit is consumed.-

which said are issues by subjecting the non-consuming fluid-cooled metalelectrode,

a fusible 'metal electrode adapted to supply fused metal to the joint,means for supplying metal to replenish said electrode as it is consumed,a second non-consuming fluidcooled electrode, and means to oscillate thelast-named electrode.

12. Apparatus for welding, comprising a non-consuming fluid-cooled metalelectrode, a fusible metal electrode adapted to supply fused metal tothe joint, means for supplying metal to replenish said electrode as itis consumed, a second non-consuming fluidcooled electrode, means tooscillate the lastnamed electrode and means for automaticallyestablishing and maintaining the arcs from said electrodes.

13. Apparatus for welding, comprising a hollow metal electrode, mean forcirculating a cooling fluid therethrough, a fusible rod or wireconstituting a consuming electrode, a holder therefor, means forautomatically feeding therod or wire to the holder as-it is fused ormelted by the arc issuing from it, and means for varying the rate atwhich the rod is fed to the holder.

14. In apparatus for electric arc welding, a hollow metal electrode,means for circulating a cooling-fluid therethrough, a pivoted levercarrying said electrode at one end, and a solenoid operatively connectedto the opposite end of the lever, said solenoid being connected incircuit with said electrode, whereby when a current flows through theelectrode, the work and the solenoid, the electrode will beautomatically lifted to establish an arc and will be maintained inraised position.

15. Apparatus for electrically welding joints between metal parts,comprising a non-consuming fluid-cooled electrode, and a fusible metalelectrode adapted to supply fused metal to the joint, the arcs springingfrom said electrodes to said metal parts.

16. Apparatus for subjecting metal to the action of an electric arc,comprising a portable tubing having juxtaposed tubular members forming atool ovate in section and providing inlet and return channels for thecirculation of a cooling medium.

17. Apparatus for electrically welding joints between metal parts,comprising a fusible metal electrode adapted to supply fused metal tothe joint when an electric arc is sprung between the electrode and themetal parts, and means controlled by the current in the circuit of saidare for automatically supplying metal to replenish said electrode as itis consumed.

18. Apparatus for subjecting metal to the action of an electric arc,comprising a nonconsuming hollow member having inlet and return channelsfor circulating a cooling medium, and an insulating covering surroundingsaid member except at the arcing In testimony whereof I afiix mysignature emll. A f 1 mm in presence of two witnesses.

9. pparatus or e ectrie we g comprising a non-consuming fluid-cooledmetal ANDBEW SMITH electrode, and a fusible metal adapted to Witnesses:supply fused metal to the weld under the EUGENE C. BRowN,

action of the are from said' electrode. Y K. HARTIG.

